Scanner and homing method of scanning module thereof

Abstract

A scanner including a casing, a scanning platform, a scanning module and a positioning plate is provided. The scanning platform is embedded in the casing and exposes a surface to carry a to-be-scanned document. The scanning module is disposed under the scanning platform. The positioning plate disposed on an inner wall of the casing is adjacent to a top side of the scanning platform. The scanning module is for capturing images of the positioning plate and the inner wall and for identifying the image corresponding to one x-axis side of the positioning plate. The scanner defines a scanning start line according to the image corresponding to the x-axis side. The scanning module is moved from the scanning start line along a y-axis direction and captures an image of the to-be-scanned document. The x-axis side and the scanning start line are perpendicular to the y-axis direction perpendicular to the top side.

1 . A scanner, comprising:
 a casing;   a scanning platform embedded in the casing and exposing a surface to carry a to-be-scanned document, wherein the scanning platform comprises a top side;   a scanning module disposed under the scanning platform; and   a positioning plate disposed on an inner wall of the casing and adjacent to the top side of the scanning platform, wherein the scanning module is used for capturing images of the positioning plate and the inner wall and for identifying the image corresponding to at least one x-axis side of the positioning plate, a scanning start line is defined by the scanner according to the image corresponding to the x-axis side, and the scanning module is moved from the scanning start line along a y-axis direction and captures an image of the to-be-scanned document;   wherein, the x-axis side and the scanning start line are substantially perpendicular to the y-axis direction, and the y-axis direction is substantially perpendicular to the top side.   
   
   
       2 . The scanner according to  claim 1 , wherein the scanning module identifies the image corresponding to the x-axis side according to the different colors between the positioning plate and the inner wall. 
   
   
       3 . The scanner according to  claim 1 , wherein the positioning plate has a body and at least one rectangular structure, the rectangular structure protrudes from the body in the direction which is substantially parallel to the y-axis direction, and the x-axis side is a side of one of the rectangular structure and the body. 
   
   
       4 . The scanner according to  claim 1 , wherein the positioning plate has at least one square hole, the square hole penetrates the positioning plate so as to expose the inner wall, the positioning plate further has four inner sides, and the x-axis side is one of the inner sides of the positioning plate. 
   
   
       5 . The scanner according to  claim 1 , wherein the scanning module is further used for identifying the images corresponding to two y-axis sides of the positioning plate, the y-axis sides are substantially perpendicular to the x-axis side and are respectively located at two sides of the positioning plate, the scanning module is homed according to the images of the y-axis sides to capture the image of the to-be-scanned document located between two boundaries. 
   
   
       6 . The scanner according to  claim 1 , wherein the inner wall has a recess, and the positioning plate is disposed in the recess. 
   
   
       7 . The scanner according to  claim 1 , wherein a luminosity of the inner wall is smaller than a black default value, and the scanning module is further used for performing black calibration according to the luminosity of the inner wall. 
   
   
       8 . A homing method of a scanning module of a scanner, comprising:
 capturing images of a positioning plate and an inner wall of a casing of the scanner, wherein the positioning plate is disposed on the inner wall of the casing and is adjacent to a top side of a scanning platform of the scanner,   identifying the image corresponding to at least one x-axis side of the positioning plate; and   defining a scanning start line according to the image corresponding to the x-axis side, wherein the scanning module is moved from the scanning start line along a y-axis direction and captures an image of a to-be-scanned document;   wherein, the x-axis side and the scanning start line are substantially perpendicular to the y-axis direction, and the y-axis direction is substantially perpendicular to the top side.   
   
   
       9 . The homing method according to  claim 8 , wherein in the identifying step, the image corresponding to the x-axis side is identified according to the different colors between the positioning plate and the inner wall. 
   
   
       10 . The homing method according to  claim 8 , wherein the positioning plate has a body and at least one rectangular structure, the rectangular structure protrudes from the body in the direction which is substantially parallel to the y-axis direction, and the x-axis side is a side of one of the rectangular structure and the body. 
   
   
       11 . The homing method according to  claim 8 , wherein the positioning plate has at least one square hole, the square hole penetrates the positioning plate so as to expose the inner wall, the positioning plate further has four inner sides, and the x-axis side is one of the inner sides of the positioning plate. 
   
   
       12 . The homing method according to  claim 8 , wherein after the capturing step, the homing method further comprises:
 identifying the images corresponding to two y-axis sides of the positioning plate, wherein the y-axis sides are substantially perpendicular to the x-axis side and are respectively located at two sides of the positioning plate; and   homing the scanning module according to the images of the y-axis sides so as to capture the image of the to-be-scanned document located between two boundaries.